Crystal Growing

Protection of Vacuum Pumps with PV Blowback Filtration Units

The exhaust gases out of Czochralski pullers used for monocrystalline ingot growing contain dust particles that form by condensation above the silicon melt. This dust needs to be filtered to protect people, the environment and the vacuum pumps.

Fine silicon dust is highly reactive and immediately oxidizes to SiO and SiO2, an exothermic reaction. Depending on the dopant, this dust can be very hazardous.

Pall has extensive experience in this application. Pall PSS stainless steel filter elements and housings in combination with our Blowback technology are the best long-term proven solution in the industry.

Traditional Filter Technology

Dust removal with disposable filters requires opening the filter housing during filter change-out, which exposes operators to dust, and contaminates the pump's environment.

Oxidation of Si/SiO to SiO2 is exothermic and traditional filter media typically cannot repeatedly withstand the high temperatures, leading to loss of filter integrity. This results in passage of the abrasive silicon, potentially damaging the pump.

Frequent filter change-outs result in long process downtimes and a high cost of ownership.

PSS Filter Media with Blowback Technology

Pall has the most efficient, proven long-term solution on the market.

The filter housing does not need to be opened for dust removal.

Cleaning is quick and automated after each cycle using the Blowback technology.

Oxidation of the Si/SiO to SiO2 occurs in the filter vessel under well controlled conditions.

Extremely robust PSS filter elements are resistant to high temperatures and provide optimum retention of the silicon dust.

These filtration units are available semi or fully automated.

Blowback units are typically in service for several years without a filter change-out.

Cost of ownership model shows return of investment (RoI) in one to two years.

No leakage, long pump life, low cost of ownership are the hallmarks of the Blowback Units.

PV Blowback Unit Set-up

Gas Purification for Czochralski Puller Tools

When crystalline defects in the ingot appear during the growth process, remelting is necessary to remove them. This is costly because it lengthens the growth cycle, negatively impacting tool throughput. Gaskleen purifiers remove moisture to the sub ppb level from argon gas used as a blanket wtih CZ Puller tools.